Electromagnetic transducers having E-shaped cores and shielding therebetween

Abstract

A magnetic transducer of the erasing type, in which the coil is pre-wound to achieve greater manufacturing economy; and in which for the same reason, and also for electromagnetic operating efficiency, the core is laminated with each lamination being of one-piece fabrication. However, the single transducing gap in the core is too small to permit threading the coil thereon. Therefore, the core is formed of flexible material so that the gap can be enlarged to accept the coil during assembly. Alternatively, the core can be fabricated initially with an enlarged gap, and the flexible core is then bent to provide a desired gap length after the coil is assembled thereon. A variational form of the invention has two erase gaps and one record-play gap with a separate coil therefor.

What is claimed is: 
     
       1. An erase-write-read magnetic transducer structure comprising: an E-shaped magnetically permeable core member having central, back and outer arms and having a first coil linked with the central arm and having the back and outer arms passing around the outside of said first coil and defining with the central arm two pairs of confronting pole piece portions constituting a pair of erasing transducing gaps of low magnetic permeability;   the back arm of said core member having two control coils linked therewith, and a potentiometer connected in parallel with said control coils for altering the flux balance there between, whereby during the record mode of operation the record and erase functions of said transducer structure may be optimized independently of one another;   said core member also having a magnetically-permeable C-shaped extension portion and a second electrically-conducting coil passing around the outside thereof and defining a pair of confronting pole piece portions constituting a write-read transducing gap of low magnetic permeability.   
     
     
       2. An erase-write-read magnetic transducer structure comprising: said transducer structure comprising a pair of transducers, each transducer including an E-shaped magnetically permeable core member having central, back and outer arms and having a first coil linked with the central arm and having the back and outer arms passing around the outside of said first coil and defining with the central arm two pairs of confronting pole piece portions constituting a pair of erasing transducing gaps of low magnetic permeability, and   said core member also having a magnetically-permeable C-shaped extension portion and a second electrically-conducting coil passing around the outside therof and defining a pair of confronting pole piece portions constituting a read-write transducing gap of low magnetic permeability;   said pair of transducers being mounted in close parallel relationship for tracing adjacent tracks in movement with respect to a recording medium;   a unitary, one-piece magnetic shielding member mounted in parallel with and between said transducers of said pair for minimizing cross-talk between said transducers;   said shielding member having an erase shield portion and a read-write shield portion in the same plane between and parallel to said transducers and said portions being made of different materials; the erase shield portion being disposed between the erase gaps of said respective transducers, and the read-write shield portion being disposed between the read-write gaps of said respective transducers, said shield portions having a joint therebetween located intermediately of each read-write gap and the adjacent erase gaps; and   a pair of generally planar web members arranged in sandwiching relation to said erase and read-write shield portions and bonded thereto to form a unitary one-piece shield construction.   
     
     
       3. An erase-write-read magnetic transducer structure comprising: said transducer structure comprising a pair of transducers, each transducer including an E-shaped magnetically permeable core member having central, back and outer arms and having a first coil linked with the central arm and having the back and outer arms passing around the outside of said first coil and defining with the central arm two pairs of confronting pole piece portions constituting a pair of erasing transducing gaps of low magnetic permeability, and   said core member also having a magnetically-permeable C-shaped extension portion and a second electrically-conducting coil passing around the outside thereof and defining a pair of confronting pole piece portions constituting a read-write transducing gap of low magnetic permeability;   said pair of transducers being mounted in close parallel relationship for tracing adjacent tracks in movement with respect to a recording medium;   a unitary, one-piece magnetic shielding member mounted in parallel with and between said transducers of said pair for minimizing cross-talk between said transducers;   said shielding member having a soft copper erase shield portion and a mu-metal read-write shield portion in the same plane between and parallel to said transducers;   the erase shield portion being disposed between the erase gaps of said respective transducers, and the read-write shield portion being disposed between the read-write gaps of said respective transducers; and   a pair of generally planar beryllium copper web members arranged in sandwiching relation to said erase and read-write shield portions and bonded thereto to form a unitary one-piece shield construction.